This invention relates to a receptacle having contacting sections which ensure an elastic, firm contact with an inserted plug pin, and, in particular, to a very small receptacle for use in an IC card and the like.
A miniature receptacle 40 to be fitted on an IC card and the like, is constructed as shown, for example, in FIG. 1. Receptacle 40 comprises cylindrical contact 41, and connection pin 42 extending from one end of contact 41. Receptacle 40 as a whole is formed of a metal sheet which has excellent elasticity. Cylindrical contact 41 has a diameter l which is formed so as to be somewhat smaller than a diameter d of plug pin 50, as shown in FIG. 2. When plug pin 50 is inserted into cylindrical contact 41, contact 41 can firmly hold and maintain contact with plug pin 50.
Such receptacles 40 are individually fitted in corresponding holes 61, which are arranged in a grid-like array in receptacle housing 60. The receptacle housing can be incorporated into, for example, an IC card. The grid-like array is of such a high density type as to permit ten receptacles to be formed within a range of, for example, 1 cm across the end face of the housing. From this it will be understood that the individual receptacles are very small in configuration.
Since contact 41 is formed so as to have a cylindrical configuration, the holding ability of contact 41 is markedly reduced due to the repeated insertion and withdrawal of the plug pin into and from the receptacle. This is due to the fact that the cylindrical contact undergoes an outwardly expanding force due to the exertion of a twisting force of the plug pin upon the cylindrical contact during insertion and withdrawal of the plug pin.